Fix dependency handling of UUDECODE_FILES (e.g. libexec/ld.aout_so on i386).
The .uue rule is defined to make "foo.xxx.uue" -> "foo.xxx". When
UUDECODE_FILES_RENAME_* is also applied, the .uue rule tries to make "foo",
not "foo.xxx". This results in that "foo.xxx" is never made and always
"foo.xxx.uue" -> "foo" is made.
Define dependency for intermediate files.
Avoid unnecessary rebuild and reinstall. (Consume 70K in obj directory.)